mirror of
https://github.com/fumiama/gofastTEA.git
synced 2026-06-05 07:50:26 +08:00
92 lines
2.4 KiB
Go
92 lines
2.4 KiB
Go
//go:build (!go1.17 && amd64) || !amd64
|
|
// +build !go1.17,amd64 !amd64
|
|
|
|
package tea
|
|
|
|
import (
|
|
"encoding/binary"
|
|
_ "unsafe" // required by go:linkname
|
|
)
|
|
|
|
// randuint32 returns a lock free uint32 value.
|
|
//go:linkname randuint32 runtime.fastrand
|
|
func randuint32() uint32
|
|
|
|
// Encrypt tea 加密
|
|
// http://bbs.chinaunix.net/thread-583468-1-1.html
|
|
// 感谢xichen大佬对TEA的解释
|
|
//go:nosplit
|
|
func (t TEA) EncryptLittleEndian(src []byte, sumtable [0x10]uint32) (dst []byte) {
|
|
lens := len(src)
|
|
fill := 10 - (lens+1)&7
|
|
dst = make([]byte, fill+lens+7)
|
|
binary.LittleEndian.PutUint32(dst, randuint32())
|
|
binary.LittleEndian.PutUint32(dst[4:], randuint32())
|
|
binary.LittleEndian.PutUint32(dst[8:], randuint32())
|
|
dst[0] = byte(fill-3) | 0xF8 // 存储pad长度
|
|
copy(dst[fill:], src)
|
|
|
|
var iv1, iv2, holder uint64
|
|
var v0, v1 uint32
|
|
for i := 0; i < len(dst); i += 8 {
|
|
holder = binary.LittleEndian.Uint64(dst[i:]) ^ iv1
|
|
v0, v1 = uint32(holder>>32), uint32(holder)
|
|
for i := 0; i < 0x10; i++ {
|
|
v0 += (v1 + sumtable[i]) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
|
|
v1 += (v0 + sumtable[i]) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
|
|
}
|
|
iv1 = (uint64(v0)<<32 | uint64(v1)) ^ iv2
|
|
iv2 = holder
|
|
binary.LittleEndian.PutUint64(dst[i:], iv1)
|
|
}
|
|
|
|
return dst
|
|
}
|
|
|
|
//go:nosplit
|
|
func (t TEA) DecryptLittleEndian(data []byte, sumtable [0x10]uint32) []byte {
|
|
if len(data) < 16 || len(data)&7 != 0 {
|
|
return nil
|
|
}
|
|
dst := make([]byte, len(data))
|
|
|
|
var iv1, iv2, holder uint64
|
|
var v0, v1 uint32
|
|
for i := 0; i < len(dst); i += 8 {
|
|
iv1 = binary.LittleEndian.Uint64(data[i:])
|
|
iv2 ^= iv1
|
|
v0, v1 = uint32(iv2>>32), uint32(iv2)
|
|
for i := 0xf; i >= 0; i-- {
|
|
v1 -= (v0 + sumtable[i]) ^ ((v0 << 4) + t[2]) ^ ((v0 >> 5) + t[3])
|
|
v0 -= (v1 + sumtable[i]) ^ ((v1 << 4) + t[0]) ^ ((v1 >> 5) + t[1])
|
|
}
|
|
iv2 = uint64(v0)<<32 | uint64(v1)
|
|
binary.LittleEndian.PutUint64(dst[i:], iv2^holder)
|
|
holder = iv1
|
|
}
|
|
|
|
return dst[dst[0]&7+3 : len(data)-7]
|
|
}
|
|
|
|
//go:nosplit
|
|
func NewTeaCipher(key []byte) (t TEA) {
|
|
if len(key) == 16 {
|
|
t[3] = binary.BigEndian.Uint32(key[12:])
|
|
t[2] = binary.BigEndian.Uint32(key[8:])
|
|
t[1] = binary.BigEndian.Uint32(key[4:])
|
|
t[0] = binary.BigEndian.Uint32(key[0:])
|
|
}
|
|
return
|
|
}
|
|
|
|
//go:nosplit
|
|
func NewTeaCipherLittleEndian(key []byte) (t TEA) {
|
|
if len(key) == 16 {
|
|
t[3] = binary.LittleEndian.Uint32(key[12:])
|
|
t[2] = binary.LittleEndian.Uint32(key[8:])
|
|
t[1] = binary.LittleEndian.Uint32(key[4:])
|
|
t[0] = binary.LittleEndian.Uint32(key[0:])
|
|
}
|
|
return
|
|
}
|